NM_000138.5:c.2956G>A

Variant names:

• chr15-48489977-C-T
• rs112287730
• NM_000138.5:c.2956G>A

Variant summary

Our verdict is Benign. Variant got -19 ACMG points: 1P and 20B. PP2 BP4_Strong BP6_Very_Strong BS1 BS2

The NM_000138.5(FBN1):​c.2956G>A​(p.Ala986Thr) variant causes a missense change. The variant allele was found at a frequency of 0.0011 in 1,614,124 control chromosomes in the GnomAD database, including 5 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★★).

• Frequency:
  • Genomes: 𝑓 0.0010 (0 hom., cov: 31)
  • Exomes 𝑓: 0.0011 (5 hom.)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Benign reviewed by expert panel U:3 B:27
• Conservation: PhyloP100: 3.94

Genes affected

FBN1 (HGNC:3603): (fibrillin 1) This gene encodes a member of the fibrillin family of proteins. The encoded preproprotein is proteolytically processed to generate two proteins including the extracellular matrix component fibrillin-1 and the protein hormone asprosin. Fibrillin-1 is an extracellular matrix glycoprotein that serves as a structural component of calcium-binding microfibrils. These microfibrils provide force-bearing structural support in elastic and nonelastic connective tissue throughout the body. Asprosin, secreted by white adipose tissue, has been shown to regulate glucose homeostasis. Mutations in this gene are associated with Marfan syndrome and the related MASS phenotype, as well as ectopia lentis syndrome, Weill-Marchesani syndrome, Shprintzen-Goldberg syndrome and neonatal progeroid syndrome. [provided by RefSeq, Apr 2016]

ACMG classification

Verdict is Benign. Variant got -19 ACMG points.

• PP2: Missense variant in the FBN1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 1311 curated pathogenic missense variants (we use a threshold of 10). The gene has 112 curated benign missense variants. Gene score misZ: 5.0644 (above the threshold of 3.09). Trascript score misZ: 8.1787 (above the threshold of 3.09). GenCC associations: The gene is linked to MASS syndrome, Weill-Marchesani syndrome, geleophysic dysplasia, Shprintzen-Goldberg syndrome, Acromicric dysplasia, familial thoracic aortic aneurysm and aortic dissection, progeroid and marfanoid aspect-lipodystrophy syndrome, ectopia lentis 1, isolated, autosomal dominant, Marfan syndrome, Weill-Marchesani syndrome 2, dominant, isolated ectopia lentis, neonatal Marfan syndrome, stiff skin syndrome.
• BP4: Computational evidence support a benign effect (MetaRNN=0.06246361).
• BP6: Variant 15-48489977-C-T is Benign according to our data. Variant chr15-48489977-C-T is described in ClinVar as [Benign]. Clinvar id is 36060.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr15-48489977-C-T is described in Lovd as [Likely_benign]. Variant chr15-48489977-C-T is described in Lovd as [Benign].
• BS1: Variant frequency is greater than expected in population nfe. gnomad4 allele frequency = 0.00104 (159/152234) while in subpopulation NFE AF= 0.00178 (121/68020). AF 95% confidence interval is 0.00152. There are 0 homozygotes in gnomad4. There are 73 alleles in male gnomad4 subpopulation. Median coverage is 31. This position pass quality control queck.
• BS2: High AC in GnomAd4 at 159 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FBN1	NM_000138.5	c.2956G>A	p.Ala986Thr	missense_variant	Exon 25 of 66	ENST00000316623.10	NP_000129.3
FBN1	NM_001406716.1	c.2956G>A	p.Ala986Thr	missense_variant	Exon 24 of 65		NP_001393645.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FBN1	ENST00000316623.10	c.2956G>A	p.Ala986Thr	missense_variant	Exon 25 of 66	1	NM_000138.5	ENSP00000325527.5

Frequencies

GnomAD3 genomes AF: 0.00105 AC: 159 AN: 152116 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.0000966

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000393

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00166

Gnomad FIN AF: 0.00179

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00178

Gnomad OTH AF: 0.000478

GnomAD3 exomes AF: 0.00118 AC: 297 AN: 251462 Hom.: 0 AF XY: 0.00131 AC XY: 178 AN XY: 135910

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000289

Gnomad ASJ exome AF: 0.0000992

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00157

Gnomad FIN exome AF: 0.00157

Gnomad NFE exome AF: 0.00175

Gnomad OTH exome AF: 0.000815

GnomAD4 exome AF: 0.00111 AC: 1617 AN: 1461890 Hom.: 5 Cov.: 31 AF XY: 0.00116 AC XY: 841 AN XY: 727246

Gnomad4 AFR exome AF: 0.0000597

Gnomad4 AMR exome AF: 0.000268

Gnomad4 ASJ exome AF: 0.000115

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00166

Gnomad4 FIN exome AF: 0.00189

Gnomad4 NFE exome AF: 0.00115

Gnomad4 OTH exome AF: 0.00129

GnomAD4 genome AF: 0.00104 AC: 159 AN: 152234 Hom.: 0 Cov.: 31 AF XY: 0.000981 AC XY: 73 AN XY: 74442

Gnomad4 AFR AF: 0.0000963

Gnomad4 AMR AF: 0.000392

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00166

Gnomad4 FIN AF: 0.00179

Gnomad4 NFE AF: 0.00178

Gnomad4 OTH AF: 0.000473

Alfa AF: 0.00128 Hom.: 1

Bravo AF: 0.000706

TwinsUK AF: 0.000809 AC: 3

ALSPAC AF: 0.000519 AC: 2

ESP6500AA AF: 0.000227 AC: 1

ESP6500EA AF: 0.00186 AC: 16

ExAC AF: 0.00151 AC: 183

Asia WGS AF: 0.000289 AC: 1 AN: 3478

EpiCase AF: 0.00136

EpiControl AF: 0.000830

ClinVar

Significance: Benign

Submissions summary: Uncertain:3 Benign:27

Revision: reviewed by expert panel

Submissions by phenotype

Marfan syndrome Uncertain:1 Benign:6

Nov 07, 2017

Center for Medical Genetics Ghent, University of Ghent

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Mar 13, 2012

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Sep 26, 2023

ClinGen FBN1 Variant Curation Expert Panel, ClinGen

Significance: Benign

Review Status: reviewed by expert panel

Collection Method: curation

NM_000138.5 c.2956G>A is a missense variant in FBN1 predicted to cause a substitution of an alanine by a threonine at amino acid 986 (p.Ala986Thr). This variant has been identified in numerous individuals with diagnoses or suspicion of Marfan syndrome in both the published literature and internal databases (PP4; PMIDs: 24793577, 26410935, 27582083, 28679693, 28387797; Bichat, Mayo, UZG, UZA); however, in at least 3 of these cases, another pathogenic variant in FBN1 was also present (BP2; Bichat). This variant has been previously reported in ClinVar as likely benign or benign by more than 20 laboratories (Variation ID: 36060). It is present in gnomAD v2.1.1 at a frequency of 0.19% (245/129170 alleles) in the European sub-population (BA1; https://gnomad.broadinstitute.org/). Computational prediction tools and conservation analysis are unclear about a predicted impact of this variant. In summary, this variant meets criteria to be classified as benign for Marfan syndrome based on the ACMG/AMP criteria applied, as specified by the ClinGen FBN1 VCEP: BA1, BP2, PP4. The pathogenic evidence code PP4 was not considered to be in conflict with this conclusion. -

Mar 11, 2015

CSER _CC_NCGL, University of Washington

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: research

- -

May 28, 2019

Mendelics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jul 09, 2015

Genomic Diagnostic Laboratory, Division of Genomic Diagnostics, Children's Hospital of Philadelphia

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases was too high to be consistent with this variant causing disease. Therefore, this variant is classified as benign. -

Familial thoracic aortic aneurysm and aortic dissection Uncertain:2 Benign:3

Mar 16, 2018

Color Diagnostics, LLC DBA Color Health

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Dec 27, 2013

Blueprint Genetics

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Nov 16, 2017

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Feb 18, 2015

Ambry Genetics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -

not provided Benign:5

Jan 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

FBN1: BS1 -

-

Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Oct 28, 2020

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is associated with the following publications: (PMID: 16220557, 24793577, 12402346, 19370756, 27582083, 26410935, 28387797, 23608731, 28679693) -

-

Genome Diagnostics Laboratory, University Medical Center Utrecht

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Oct 10, 2024

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not specified Benign:3

Dec 02, 2014

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

p.Ala986Thr in exon 25 of FBN1: This variant is not expected to have clinical si gnificance because it has been identified in 0.198% (134/67678) of non-Finnish E uropean chromosomes by the Exome Aggregation Consortium (ExAC, http://exac.broad institute.org; dbSNP rs112287730). This variant has been reported in 5 individua ls with clinical features of Marfan syndrom and/or connective tissue disorder, b ut was also identified in 2 unaffected relatives from two families (Rommel 2002, Frederic 2009, Aboni 2013, Lerner-Ellis 2014). -

-

Genome Diagnostics Laboratory, Amsterdam University Medical Center

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Aug 15, 2016

Eurofins Ntd Llc (ga)

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Connective tissue disorder Benign:2

Nov 01, 2016

Center for Human Genetics, Inc, Center for Human Genetics, Inc

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Dec 01, 2021

Genome Diagnostics Laboratory, The Hospital for Sick Children

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Stiff skin syndrome Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases was too high to be consistent with this variant causing disease. Therefore, this variant is classified as benign. -

Weill-Marchesani syndrome Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases was too high to be consistent with this variant causing disease. Therefore, this variant is classified as benign. -

Geleophysic dysplasia Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases was too high to be consistent with this variant causing disease. Therefore, this variant is classified as benign. -

Acromicric dysplasia Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases was too high to be consistent with this variant causing disease. Therefore, this variant is classified as benign. -

FBN1-related disorder Benign:1

May 12, 2020

PreventionGenetics, part of Exact Sciences

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Marfan syndrome;C4707243:Familial thoracic aortic aneurysm and aortic dissection Benign:1

Feb 02, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Ectopia lentis 1, isolated, autosomal dominant Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases was too high to be consistent with this variant causing disease. Therefore, this variant is classified as benign. -

Marfan syndrome;C0265287:Acromicric dysplasia;C1858556:MASS syndrome;C1861456:Stiff skin syndrome;C1869115:Weill-Marchesani syndrome 2, dominant;C3280054:Geleophysic dysplasia 2;C3541518:Ectopia lentis 1, isolated, autosomal dominant;C4310796:Progeroid and marfanoid aspect-lipodystrophy syndrome Benign:1

Mar 30, 2021

Center for Genomics, Ann and Robert H. Lurie Children's Hospital of Chicago

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

FBN1 NM_000138.4 exon 25 p.Ala986Thr (c.2956G>A): This variant has been reported in the literature in at least 4 individuals with features of connective tissues disorders (Lerner-Ellis 2014 PMID:24793577, Arnaud 2017 PMID:27582083, Cousin 2017 PMID:28679693, Girdauskas 2017 PMID:28387797). However, this variant is also present in 0.1% (20/10474) of Finnish alleles in the Genome Aggregation Database (https://gnomad.broadinstitute.org/variant/15-48489977-C-T?dataset=gnomad_r3) and is present in ClinVar, with several labs classifying this variant as benign or likely benign (Variation ID:36060). Evolutionary conservation and computational predictive tools suggest that this variant may not impact the protein. In summary, data on this variant suggests that this variant does not cause disease, but requires further evidence. Therefore this variant is classified as likely benign. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.10
BayesDel_addAF	Benign	-0.21	T
BayesDel_noAF	Uncertain	-0.070
CADD	Uncertain	25
DANN	Pathogenic	1.0
Eigen	Uncertain	0.30
Eigen_PC	Uncertain	0.39
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.92	D
M_CAP	Uncertain	0.096	D
MetaRNN	Benign	0.062	T
MetaSVM	Uncertain	0.46	D
PrimateAI	Uncertain	0.59	T
PROVEAN	Uncertain	-2.4	N
REVEL	Uncertain	0.47
Sift	Benign	0.10	T
Sift4G	Benign	0.38	T
Vest4		0.52
MVP		0.80
MPC		0.89
ClinPred		0.072	T
GERP RS		5.7

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs112287730; hg19: chr15-48782174;